With the amount of stuff he was given from the start he is not living in 10th century conditions.
Established buildings, lots of livestock, generous food supplies, a well, advanced cooking facilities, outhouse, tools. He is living the life of an obscenely healthy noble in a small prosperous village whose people left him well stocked on a generous plant of land that is somehow unmolested by thieves and brigands. You would not have that level of material well-being on your own. It would have taken 50 years with multiple generations of sweat, toil, trial and error to get to that point. Even if you had it you wouldn't be able to maintain it.
People can survive with more primitive technology, people can survive with less material goods. Was that ever in question? Look to any impoverished area of the earth. The true value of the experiment is IMHO in studying the psychological effects of technology deprivation and extreme isolation.
I could do it. I would not want to do it.
Alone for 8 months with nothing to do but eat, sleep, shit, and piss. No internet and a boatload of manual chores. With everything being prefabricated there's even less variety in your routine to pass the time.
But hey the guy got funding for an 8 month vacation to screw around in the woods. He presumably enjoyed it. This is a win any way you slice it.
